Ophthalmic apparatus and method for increasing the resolution of aliased ophthalmic images

Abstract

A method for producing an image with an increased resolution from a plurality of aliased ophthalmic images having an original resolution is described. The method comprises the steps of—providing an imaging system capable of acquiring said aliased ophthalmic images,—acquiring said aliased ophthalmic images by the imaging system, thereby generating non-integer pixel displacements between said images by using voluntary or involuntary eye movements,—determining the displacements between said images, and—producing an image with an increased resolution in an overlapping area of said aliased ophthalmic images compared to the original resolution of said images, based on said images and said displacements, using a super-resolution algorithm.

1. A method for producing an image with an increased resolution from a plurality of aliased ophthalmic images having an original resolution, the increased resolution being higher than the original resolution, the method comprising:
 providing a imaging system capable of acquiring said plurality of aliased ophthalmic images, 
 acquiring said plurality of aliased ophthalmic images by the imaging system, thereby generating non-integer pixel displacements between said plurality of aliased ophthalmic images by using voluntary or involuntary eye movements, 
 determining displacements between said plurality of aliased ophthalmic images, and 
 producing the image with an increased resolution in an overlapping area of said plurality of aliased ophthalmic images, based on said plurality of aliased ophthalmic images and said determined displacements, using a super-resolution algorithm. 
 
     
     
       2. The method of  claim 1  wherein said imaging system acquires single aliased ophthalmic images, combining them into an image series by means of internal or external data memory. 
     
     
       3. The method of  claim 1  wherein said imaging system combines the plurality of aliased ophthalmic images into an image series or video stream. 
     
     
       4. The method of  claim 1  wherein said displacements between said plurality of aliased ophthalmic images are determined from said plurality of aliased ophthalmic images by minimizing a distance function of said plurality of aliased ophthalmic images. 
     
     
       5. The method of  claim 2  wherein said displacements between said plurality of aliased ophthalmic images are determined from said plurality of aliased ophthalmic images by minimizing a distance function of said plurality of aliased ophthalmic images. 
     
     
       6. The method of  claim 3  wherein said displacements between said plurality of aliased ophthalmic images are determined from said plurality of aliased ophthalmic images by minimizing a distance function of said plurality of aliased ophthalmic images. 
     
     
       7. The method of  claim 1  wherein said displacements between said aliased ophthalmic images are determined by an external device such as an eye tracker. 
     
     
       8. The method of  claim 2  wherein said displacements between said aliased ophthalmic images are determined by an external device such as an eye tracker. 
     
     
       9. The method of  claim 3  wherein said displacements between said aliased ophthalmic images are determined by an external device such as an eye tracker. 
     
     
       10. The method of  claim 1  wherein said non-integer pixel displacements are introduced by natural involuntary eye movements. 
     
     
       11. The method of  claim 2  wherein said non-integer pixel displacements are introduced by natural involuntary eye movements. 
     
     
       12. The method of  claim 3  wherein said non-integer pixel displacements are introduced by natural involuntary eye movements. 
     
     
       13. The method of  claim 4  wherein said non-integer pixel displacements are introduced by natural involuntary eye movements. 
     
     
       14. The method of  claim 5  wherein said non-integer pixel displacements are introduced by natural involuntary eye movements. 
     
     
       15. The method of  claim 1  wherein said non-integer pixel displacements are introduced by inducing eye movements using a visual stimulus. 
     
     
       16. The method of  claim 2  wherein said non-integer pixel displacements are introduced by inducing eye movements using a visual stimulus. 
     
     
       17. The method of  claim 3  wherein said non-integer pixel displacements are introduced by inducing eye movements using a visual stimulus. 
     
     
       18. The method of  claim 4  wherein said non-integer pixel displacements are introduced by inducing eye movements using a visual stimulus. 
     
     
       19. The method of  claim 5  wherein said non-integer pixel displacements are introduced by inducing eye movements using a visual stimulus. 
     
     
       20. The method of  claim 9  wherein the step of acquiring said plurality of aliased ophthalmic images is synchronized with a movement of said visual stimulus. 
     
     
       21. The method of  claim 1 , further comprising:
 determining the displacements between the plurality of aliased ophthalmic images due to optical, geometrical or other distortions, and 
 correcting for these distortions. 
 
     
     
       22. The method of  claim 1  further comprising:
 dividing each of said aliased ophthalmic images into a number N smaller images, 
 grouping said smaller images together into N series of smaller images, 
 determining displacements between the smaller images for each of the N series of smaller images, and 
 producing an image with a an increased resolution, one image for each of the N series of smaller images. 
 
     
     
       23. The method of  claim 1  further comprising:
 dividing each of said aliased ophthalmic images into a number N smaller images, 
 grouping said smaller images together into N series of smaller images, 
 determining displacements between the smaller images for each of the N series of smaller images, 
 producing an image with a an increased resolution, one image for each of the N series of smaller images, 
 determining the displacements between the plurality of aliased ophthalmic images due to optical, geometrical or other distortions, and 
 correcting for these distortions. 
 
     
     
       24. The method of  claim 1  further comprising:
 dividing each of said aliased ophthalmic images into a number N smaller images, 
 grouping said smaller images together into N series of smaller images, 
 determining displacements between the smaller images for each of the N series of smaller images, 
 producing an image with a an increased resolution, one image for each of the N series of smaller images, 
 determining the displacements between the plurality of aliased ophthalmic images due to optical, geometrical or other distortions, and 
 correcting for these distortions and wherein the N images with an increased resolution are stitched together to produce one larger image. 
 
     
     
       25. An ophthalmic apparatus for producing an image with an increased resolution from a plurality of aliased ophthalmic images having an original resolution, the increased resolution being higher than the original resolution, the apparatus comprising:
 an imaging system for acquiring said plurality of aliased ophthalmic images, thereby generating non-integer pixel displacements between said plurality of aliased ophthalmic images by using voluntary or involuntary eye movements, and 
 a processing unit for determining the displacements between said plurality of aliased ophthalmic images, and producing an image with an increased resolution in an overlapping area of said plurality of aliased ophthalmic images, based on said plurality of aliased images and said displacements, using a super-resolution algorithm. 
 
     
     
       26. The ophthalmic apparatus according to  claim 25  wherein the imaging system is further arranged to provide, in use, a visual stimulus during the acquisition of the plurality of aliased ophthalmic images. 
     
     
       27. The ophthalmic apparatus according to  claim 25  wherein the imaging system is substantially stationary during the acquisition of the plurality of aliased ophthalmic images. 
     
     
       28. The ophthalmic apparatus according to  claim 25  wherein the processing unit is arranged to, in use, synchronize the acquiring of said plurality of aliased ophthalmic images by the imaging system with a movement of said visual stimulus. 
     
     
       29. The ophthalmic apparatus according to  claim 25  wherein the processing unit is arranged to, in use, synchronize the acquiring of said plurality of aliased ophthalmic images by the imaging system with a movement of said visual stimulus and wherein the imaging system is substantially stationary during the acquisition of the plurality of aliased ophthalmic images.